package com.atguigu.gulimall.cart.interceptor;

import com.atguigu.common.constant.AuthConstant;
import com.atguigu.common.constant.CartConstant;
import com.atguigu.entity.vo.MemberResponseVo;
import com.atguigu.gulimall.cart.entry.vo.UserInfoTo;
import org.apache.commons.lang.StringUtils;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.util.UUID;

/**
 * 在执行目标方法之前，判断用户的登录状态，并分装传递给controller目标请求
 * 拦截器需要工作，还需要在WebMvcConfigurer的addInterceptors里面配置
 */
@Component
public class CartInterceptor implements HandlerInterceptor {

    //ThreadLocal同一线程共享数据
    //从拦截器->controller->srvice->dao-。。。都是同一个线程
    public static ThreadLocal<UserInfoTo> threadLocal = new ThreadLocal<>();

    /**
     * 目标方法执行之前 return  true放行；
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        UserInfoTo userInfoTo = new UserInfoTo();

        HttpSession session = request.getSession();
        MemberResponseVo member = (MemberResponseVo) session.getAttribute(AuthConstant.LOGIN_USER);
        if (member != null){
            //用户登录了
            userInfoTo.setUserId(member.getId());
        }

        Cookie[] cookies = request.getCookies();
        if (cookies != null && cookies.length > 0){
            for (Cookie cookie : cookies) {
                //user-key
                String name = cookie.getName();
                if (CartConstant.TEMP_USER_COOKIE_NAME.equals(name)){
                    userInfoTo.setUserKey(cookie.getValue());
                    userInfoTo.setTempUser(true);
                }
            }
        }

        //如果第一次没有临时用户，需要生成一个
        if (StringUtils.isEmpty(userInfoTo.getUserKey())){
            String uuId = UUID.randomUUID().toString();
            userInfoTo.setUserKey(uuId);
        }

        threadLocal.set(userInfoTo);

        return true;
    }

    /**
     * 业务执行之后，分配临时用户，让浏览器保存
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

        UserInfoTo userInfoTo = threadLocal.get();
        if (!userInfoTo.isTempUser()){
            //如果不判断，持续延长临时用户的过期时间
            Cookie cookie = new Cookie(CartConstant.TEMP_USER_COOKIE_NAME, userInfoTo.getUserKey());
            cookie.setDomain("gulimall.com");
            cookie.setMaxAge(CartConstant.TEMP_USER_COOKIE_TIME);//过期时间

            response.addCookie(cookie);
        }
    }
}
